The present invention concerns a noise dampening apparatus for a video signal processing system, and more particularly an apparatus for not only automatically dampening noises contained in the luminance signal (Y signal), but also enabling the user to selectively dampen the noises.
Generally, the luminance signal Y of the three primary color (R,G,B) signals combined with the chrominance signal contains the noises of the transmission channel, so that it is difficult to reproduce the original image. Under such a circumstance, the noises contained in the Y signal are removed by using a noise dampening apparatus in the receiving end. Moreover, the Y signal has visual characteristics very susceptible to the eye, which requires to be properly treated.
Referring to FIG. 1 for illustrating a conventional noise dampening apparatus, the level of the Y signal received through input terminal 1H is adjusted by a resistor R1, and the noises contained in the Y signal are removed by a noise dampening processor 20. Then the Y signal is delivered through a resistor R2 to an output terminal 2H connected with a video signal output means.
If the user changes the connecting position of a switch 4 from "1" to "2", the Y signal is delivered through a buffer 3 and resistor R2 to the output terminal 2H. Namely, the Y signal is directly sent to the output terminal not passing the noise dampening processor 20. In this case, it is virtually impossible for the user to properly select the position of the switch according to the received video signal in order to dampen the noises.